Fin Stabilizer

ABSTRACT

A vessel hull stabilization system includes a housing having a rotatable shaft mounted thereto, the shaft configured to connect to a fin such that the fin is located on an outside of the vessel hull and the housing is located on an inside of the vessel hull. A drive system is mounted to the housing and includes a motor and a drive element. The motor is connected to a central shaft of the drive element and an outer element of the drive element is connected to the fin shaft. The drive element includes a plurality of teeth positioned between the outer element and the central shaft such that when the motor rotates the central shaft, the plurality of teeth oscillate in a direction perpendicular to an axis of the central shaft to interact with and rotate the outer element. A controller receives sensor readings to determine control signals to send to the motor(s) to impart rotation of the fin.

FIELD OF THE INVENTION

The invention relates to stabilizers and control systems for stabilizersthat are used for marine vessels both when making headway and at rest(e.g. at anchor, or zero speed).

BACKGROUND OF THE INVENTION

Fin roll stabilizers are commonly mounted to the hull of a vessel belowthe waterline, usually within the middle one third of the vessel'swaterline length and close to the turn of the bilge. These finstypically rotate about an axis that is perpendicular to the lengthwiseaxis of the vessel. The stabilizer fins are generally aligned parallelto the lengthwise axis of the vessel and rotation of these fins reducesroll of the vessel. The fin roll stabilizers act in some ways that aresimilar to ailerons on an airplane.

Many traditional fin roll stabilizers for marine vessels are poweredhydraulically. In order to create a functioning stabilizing system, acomplex setup of hydraulic plumbing, valves, cylinders and pumps areneeded to operate and control the stabilizer. In addition, a reservoirmust be provided to supply the pumps with hydraulic fluid and a coolingsystem and filter is needed to prevent overheating and to keep the fluidclean. The hydraulic system components all need connection with hose orpipe which can run long distances within a vessel and can be difficultto install and require maintenance.

Electrical sensors and controls are then needed to operate variousvalves within the hydraulic system to allow the stabilizer fins to movethrough varying degrees of rotation that depend on vessel speed and waveconditions that are causing the vessel to roll.

The hydraulic system also comes with added environmental concernsassociated with hydraulic oil because a leak in the system can bleedinto the bilge of the vessel and be pumped out with bilge water into theocean or other body of water where the marine vessel is operating.

The hydraulic fluid is often put under high pressure such that theassociated parts within the system must be designed to withstand thatsubstantial pressure. In addition, air in the hydraulic system can causecontrol problems and when the air bubbles collapse they generate intenselocalized heat in the hydraulic oil leading to system overheating andearly hydraulic component failure. Air in the system can also causeobjectionable noise and vibration transmitted throughout the vessel viathe interconnecting hydraulic piping. Routine maintenance or servicingof an otherwise closed hydraulic system, such as changing a hose or avalve, can easily introduce debris or contaminants that can causeintermittent problems that are very difficult to diagnose, requirecomplete system flushing and can lead to expensive repairs.

Another concern of a shipboard hydraulic system is fire. At higherpressures the hydraulic system is more prone to leaks and when a leakoccurs the oil can mist or spray onto hot surfaces in the vessel'smachinery spaces or be vaporized, and when exposed to a source ofignition vaporized oil causes fire.

An alternative to hydraulics has been direct drive electric motors thatrotate the fin shaft via a planetary gear set. However, planetary geararrangements are prone to backlash and positioning errors, and thoseerrors increase as the gears experience wear. Strain wave gear setseliminate backlash, but are less efficient, are limited in torquecapacity and are prone to ratcheting phenomenon in momentary peakconditions (this condition is called dedoidal and can damage the drive).

SUMMARY OF THE INVENTION

Therefore, it is an object of the invention to provide an oscillatingseparate individual sliding tooth drive system using a logarithmicspiral that allows power to be transmitted by multiple teeth in surfacecontact for the purpose of rotating a stabilization fin with improvedtorque control and reduced or zero backlash.

It is a further object of the invention to provide for flexibleplacement and orientation of motor and drive elements to provide for theability to fit in small spaces, to provide improved access forrepair/adjustment.

It is a further object of the invention to allow for use of standardizedand interchangeable components to allow for the number of motors whichmake up the stabilizer to be changed to accommodate varied fin andtorque requirements.

These and other objects are achieved by providing a vessel stabilizationsystem including a housing having a rotatable fin shaft mounted thereto,the fin shaft configured to connect to a fin such that the fin islocated outside of the vessel hull below the waterline and the housingis located inside of the vessel hull. A drive system is directly orindirectly mounted to the housing and includes a motor and a driveelement. The system may also include gearing between the motor and driveelement, and/or gearing between the drive element and the fin shaft. Themotor is directly or indirectly connected to a central shaft of thedrive element and an outer element of the drive element is connected tothe fin shaft. The drive element includes a plurality of teethpositioned between the outer element and the central shaft such thatwhen the motor rotates the central shaft, the plurality of teethoscillate in a direction perpendicular to an axis of the central shaftto interact with and rotate the outer element.

The terms “first” and “second” are used to distinguish one element, set,data, object or thing from another, and are not used to designaterelative position or arrangement in time.

The terms “coupled”, “coupled to”, “coupled with”, “connected”,“connected to”, and “connected with” as used herein each mean arelationship between or among two or more devices, apparatus,components, systems or subsystems constituting any one or more of (a) aconnection, whether direct or through one or more other devices,apparatus, components, systems or subsystems, and/or (b) a functionalrelationship in which the operation of any one or more devices,components, systems or subsystems, in whole or in part, on the operationof any one or more others thereof.

In certain aspects each drive unit assembly includes a plurality ofdrive systems each mounted to said housing wherein the motor extendsoutwardly relative to the central shaft at an angle normal to withoutintersecting the axis of the central shaft. In still other aspects theplurality of drive systems are configured to be mounted to said housingsuch that each drive system is configured to be positioned so that theangle of the motor is adjustable to at least two different positions incertain embodiments, these two different positions are at least 90degrees apart.

In certain aspects a vessel hull stabilization system is providedincluding a housing having a shaft mounted thereto, the shaft configuredto connect to a fin such that the fin is located on an outside of thevessel hull and the housing is located on an inside of the vessel hull.A drive system is mounted to the housing and includes a motor and adrive element, the motor is connected to a central rotating element ofthe drive element and an outer rotating element of the drive element isconnected to the shaft. The drive element includes a plurality of teethpositioned between the outer rotating element and the central rotatingelement such that when the motor rotates the central rotating element,the plurality of teeth oscillate in a direction perpendicular to an axisabout which the central rotating element rotates to thereby causerotation of the outer element.

In some aspects the drive system includes multiple drive systems eachmounted to the housing so that the motor extends outwardly relative tothe central shaft at an angle normal to without intersecting the axis ofthe central shaft. In certain aspects the drive system includes multipledrive systems each mounted to the housing, where the motor of each drivesystem extends parallel to the axis. In certain aspects the drivesystems are configured to be mounted to the housing such that each drivesystem is configured to be positioned so that the angle of the motor isadjustable to at least two different positions at least 90 degreesapart. In other aspects the drive systems are configured to be mountedto the housing such that each drive system is configured to bepositioned so that the angle of the motor is adjustable to at least twodifferent positions which are adjacent and range from 5 to 20 degreesapart. In other aspects the two different positions are 8-14 degreesapart. In certain aspects the at least two different positions includeat least ten different positions. In other aspects, the drive systemsare configured to be mounted to the housing such that each drive systemis configured to be positioned so that the angle of the motor isadjustable to at least four different positions. In other aspects, thedrive systems are configured to be mounted to said housing such thateach drive system is configured to be positioned so that the angle ofthe motor is adjustable to at least six different positions. In otheraspects, the angle of the motor adjustable to at least eight differentpositions.

In certain aspects, the outer rotating element of the drive element isconnected directly to the shaft such that the fin and the outer rotatingelement rotate at the same angular velocity. In still other aspects, theouter rotating element of the drive element has a first gear connectedthereto which meshes with a second gear connected to the shaft. In otheraspects, the second gear has less than 180 degrees of teeth.

In other aspects, the system is provided with a plurality of plateswhich connect to the housing, at least a first one of the plates is afirst plate and includes a central hole and a plurality of radial holes.In still other aspects, the drive element is configured to connect tothe first one of the plurality of plates at the plurality of radialholes such that an element which is caused to rotate by the motor passesthrough the central hole.

In still other aspects, at least two first ones of the plurality ofplates and the drive system comprise two drive systems, each with adrive element and motor, each one of said two drive systems connected toone of the first plates.

In other aspects, a vessel hull stabilization system is provided andincludes a housing having a shaft mounted thereto, the shaft configuredto connect to a fin such that the fin is located on an outside of thevessel hull and the housing is located on an inside of the vessel hull.A drive system is mounted to the housing and includes a motor and adrive element, the motor connected to a central rotating element of thedrive element and an outer rotating element of the drive elementconnected directly to the shaft such that the fin and the outer rotatingelement rotate at the same angular velocity. The drive element furtherincludes teeth positioned between the outer rotating element and thecentral rotating element such that when the motor rotates the centralrotating element, the plurality of teeth oscillate in a directionperpendicular to an axis about which the central rotating elementrotates to thereby cause rotation of the outer element.

In certain aspects, the motor includes a rotating element which connectsto the central rotating element, the rotating element of the motorrotates about the axis. In other aspects, the motor includes a rotatingelement which connects to the central rotating element, the rotatingelement of the motor rotates about a second axis normal to the axis.

In yet other aspects a stabilization system for a vessel is providedwith a housing having a shaft mounted thereto, the shaft configured toconnect to a fin such that the fin is located on an outside of thevessel hull and the housing is located on an inside of the vessel hull.Multiple plates are provided and at least a first and second whichinclude an inner hole and a plurality of outer holes radially around theinner hole. At least two drive systems are included and each have amotor and drive element, the drive element configured to connect to theshaft through the inner hole in one of the plurality of plates. Thedrive element is connected to its corresponding one of the plurality ofplates such that it is removable and rotatable about the central hole inat least two positions which are at least 5 degrees apart. In certainaspects the multiple plates includes at least one plate without innerand outer holes therein. In certain aspects the plates are removablyconnected to the housing. In certain aspects the plates are eachrepositionable on the housing and relative to others of said pluralityof plates. In other aspects the drive element includes a first gear andthe shaft includes a second gear which meshes with the first gear totransfer torque from the motor to the shaft.

The stabilization systems may include at least one sensor and at leastone controller in communication with the motor(s) and the at least onesensor, the at least one controller sends signals to the motor(s) tochange a position of the fin based on readings from the at least onesensor.

In certain aspects, the shaft has a diameter measured at a firstlocation where the shaft meets the housing and the system has a heightmeasured from the first location to a maximum inboard location thereof,the shaft extending outboard from the housing from the first location.The height may be 2-20, 3-15 3.5-10 and/or 4-7 times the diameter. Inother aspects upper and lower bearings are located in the housing suchthat the shaft is supported by the upper and lower bearings, the lowerbearing positioned closer to a first location where the shaft meets thehousing than the upper bearing, a bearing spacing measured between theupper and lower bearings. The height may be 1.05-8, 1.1-6, 1.2-5 and/or1.05-3 times the bearing spacing.

Other objects of the invention and its particular features andadvantages will become more apparent from consideration of the followingdrawings and accompanying detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a drive unit assembly for a finstabilizer according to an embodiment of the present invention

FIG. 2 is a top view of FIG. 1.

FIGS. 3-8 are top views of FIG. 1 in alternate configurations of thedrive system(s) in various mounting locations and orientations.

FIG. 9 is side perspective view of the drive unit assembly of FIG. 1.

FIG. 10 is a perspective view of a drive system directly connected tothe fin shaft with an optional right angle gear box.

FIG. 11 is a perspective view of a drive system directly connected tothe fin shaft.

FIG. 12 is a perspective exploded view of a single drive system.

FIGS. 13A-B show top and perspective views a component of the devices ofFIGS. 1-12 where the drive assembly attaches to the stabilizer.

FIGS. 14A-C show one embodiment of a drive element which could be usedwith respect to FIGS. 1-12.

FIG. 15 shows an exploded view of FIG. 11.

FIG. 16 shows a partial cross section view of FIG. 10.

DETAILED DESCRIPTION OF THE INVENTION

Referring now to the drawings, wherein like reference numerals designatecorresponding structure throughout the views. The following examples arepresented to further illustrate and explain the present invention andshould not be taken as limiting in any regard.

FIG. 1 shows an example drive unit assembly 1 for a fin stabilizer whichemploys the oscillating tooth based drive system 4, 4′ to drive theshaft 8 which rotates the fin 18 attached thereto. An example fin thatattached to a shaft similar to that shown in FIG. 1 is also shown anddescribed in U.S. Pat Pub No 2016/0121978, the content of which isincorporated by reference herein. It is understood that other driveelements made gears and other transmission devices may be employed inconnection with this system. As shown, the drive unit assembly 1 isconnected to a controller 100 which receives sensor data from sensor(s)110 to determine what stabilizing commands are necessary based on theconditions and movement of the ship. Commands are communicated to themotors 2, 2′ to change a position of the fin 18 to thereby enhancestability of or adjust the position of the vessel. For example, tocounteract roll.

FIG. 1 provides two motors 2,2′ which respectively operate anoscillating tooth based drive element. An example oscillating toothbased drive element is shown and described in U.S. Pat. Pub. No.2009/0205451, the content of which is incorporated by reference herein.

Therefore, motor 2 is coupled to an internal shaft or central rotatingelement of the drive element 4 which rotates to thereby drive theoscillating motion of the teeth which causes an element outwards of thecentral element to rotate. In certain embodiments a gear 14 extendsbelow plate 6 and within housing 12. The gear 14 interlocks with asecond gear 16 which is connected to shaft 8, and also positioned in thehousing 12.

FIG. 9 shows one example of the gear 14 and the second gear 16 connectedto the shaft 8. The drive element 4 and motor 2 are not included in thedrawing of FIG. 9. FIG. 12 shows additional detail on the second gear 16in that in the single motor embodiment, this gear may only include teetharound about 120 degrees to enable a corresponding amount of angularposition travel of the fin. In the embodiment where multiple motors areused, it would be understood that the second gear 16 may extend aroundthe entire 360 degrees such that the additional motors and their gears14 can mesh with gear 16 to turn the fin 18.

As shown in FIG. 2, the drive system can be positioned at a wide rangeof angles relative to the housing and additional drive systems can bemounted to the housing 12 to increase the torque capabilities such thata single housing can be used for different fin sizes. Positions A-E arebut some examples of how the motor can be positioned.

In certain instances a larger fin could be used an may require moretorque to rotate and thus need more drive systems whereas a smaller finwould require less torque and thus fewer drive systems. Depending on thedrive system mounting location on the housing and clearance as to otheritems in the ship, the drive system would be positioned to allow forappropriate clearances between other ship parts. In other aspects, theposition may be selected to allow for easy access forrepair/maintenance. A variety of position options are shown at FIGS. 3-8but it is understood that the positions shown are not exhaustive of alloptions to position the drive systems as the positions may be mixed andmatched as appropriate for the particular vessel. For example axis 33can be positioned such that the motor is to the right of the attachmentpoint (FIG. 5), to the left of the attachment point (FIG. 3) or at avariety of angles between these locations around a 360 degree reference.Furthermore, different configurations of the securing plates 6, 6′ etcare shown in FIGS. 3-8. Notably, FIG. 3 has one plate 6 whereas FIG. 6has two plates 6 but they are positioned in different locations relativeto the stabilizer. Generally, the housing 12 will be mounted to the hullin a specific orientation, generally so the fin is parallel to thedirection of travel of the vessel in the neutral position. Then, the useof three or optionally four different motor configurations and locationsare used to assemble the plates to locate the motors as desired. Plate6″ is used to cover the center area of the housing and one of the outerlocations where a motor could go, but due to the layout of the housingand the bolts and bolt holes which connect the plates 6, 6′ and 6″ tothe housing, the plates can be assembled in a variety of differentconfigurations to enable customized placement of motors, depending onthe specific application. As shown, plates 6, 6′ and 6″ can be connectedto the housing with bolts 66 or screws or the like.

The motor in each instance shown in FIGS. 3-8 extends at a directiongenerally perpendicular or normal to the fin axle/shaft (axis 30) andthe angle of this direction can be adjusted depending on how the vesselis configured and what the space/access requirements are. It is alsounderstood that in the multiple motor configuration, one or more motorsmay be positioned such that they extend such that the rotating elementof the motor is generally parallel to the fin axle/shaft (i.e. out ofthe page). It is understood that motors may be mixed and matched inperpendicular and parallel configurations, depending on the requirementsof the vessel, space constraints and other considerations. It is alsounderstood that the motor orientation where the motor axis 33 isparallel to axis 30 can be used. For example, see FIG. 1, motor 2′ anddrive element 4′. It is understood that different motor configurationscan be mixed and matched and positioned and directed in a variety ofways to account for space and other constraints for the system.

FIG. 10 provides a direct drive system where gear 14 and second gear 16are not used. FIG. 11 provides a drive system where the motor is mounteddirectly to the drive element. FIG. 12 provides an exploded view of oneembodiment of a drive unit assembly. The angled motor element 44 may betwo beveled gears with equal numbers of teeth such that no step up/downis accomplished. Alternately, gearing may be used in the angled element44. Other transmission devices or elements other than gears may be usedto accomplish the right angle power transmission features. It is alsounderstood that although perpendicular/normal and parallel motorconfigurations are shown, the system could implemented with angledelements 44 that are at any angle between 0 and 90 degrees, depending ondesign requirements and considerations. Typically more than 90 degreeswould not be anticipated however, it is understood that angles greaterthan 90 degrees could be employed for the angle drive element 44.

To enable the motor to be re-positioned at a variety of angles aconnector, the housing 12 includes a plate 6 with a plurality of outerholes 130 which may be threaded and positioned around a larger center orinner hole 132. The center hole allows the drive element to connect tothe shaft either directly or indirectly via gears or other similartorque transfer devices. The outer holes are arrange radially around thecenter or inner hole. The outer holes may also be through holes. In thethreaded embodiment, a number of bolts 92 pass through holes in thedrive element housing 44 to connect to the threaded holes. If the outerholes in the plate 6 are not threated, a combination of nuts/bolts andwashers are used. The drive element housing 44 includes a number of boltholes 100 spaced radially there around such that the bolts 46 may beremoved. This would then allow the drive element housing 44 to berotated to a different position and thus direct the motor in a differentdirection relative to the shaft axis. The foregoing enables the motorsto be positioned in a variety of ways to accommodate tight spaces thatthe fin stabilizer system often operates in.

As also seen in FIG. 1, the plate 6 may be comprised of a plurality ofdiscreet plates. FIG. 1 shows four plates. Thus, the components of thesystem from the housing 12 down can be uniform across multiple power andfin sizes/configurations and the plates 6 may be interchanged withdifferent plates to increase/decrease the number of motors used. Forexample, the specific plate 6 referred to in FIG. 1 includes the centerhole and outer holes to enable the drive element 4 to be connectedthereto. If FIG. 1 was changed to be a one motor embodiment, the plate 6could be replaced with plate 6′ or to add additional power to thesystem, plate 6 could be duplicated and the duplicate could replaceplate 6′ and another motor and drive element could be added to thesystem. Plates can be removed/replaced via bolts or screws which passthrough holes 134.

Referring to FIGS. 14A-C, the drive element 4 is shown with its innerworkings exposed. The motor is connected to the central element 104 andthis connection may be made via bolts through the holes 102. Otherconnection methodologies can be employed. This center element includesan outer cam surface which in the embodiment shown is generally oval orelliptical in shape. This cam shape as it turns (see 14B and 14C fordifferent positions) causes the teeth 106 to move in and out relative tothe central axis. This in turn causes the teeth 106 to progressivelystep around to different of the outer gear teeth 108. The outer gearteeth 108 are fixed in position relative to the outer housing whichincludes the securing holes 100. This motion causes the inner ringthrough which the teeth 106 pass to rotate in a way that provides thegearing advantage required to rotate the fin through water. The ring 114may generally be a hollow shaft with radial holes which retain the teeth106. Chain or connection element 112 extends around the cam surface andensures that the teeth 106 are positioned correctly to enable the inwardand outward oscillating motion. As can be seen with respect to FIG. 14A,the top and bottom teeth 106 are in contact with the outer gear element108 whereas the side teeth are not. In comparison to FIG. 14B, the innerelement 104 is rotated about 60 degrees and different teeth are now incontact with outer gear element 108. As can be seen in FIG. 14B, theteeth at approximately vertical is at the tip of the top gear tooth suchthat the two points align. Other teeth are not centrally aligned attheir tips such that when outward motion of the tooth happens, the tipshape tends to cause the tooth and outer gear 108 to align and center,this causes rotational motion of the outer element or ring 114 which isthen connected to the fin shaft or other gearing to transmit torque tothe fin.

As shown in FIG. 15, the motor shaft 200 aligns with the center of thedrive element 4 and thus the rotation axis of the inner 104 and outer114 elements thereof. Further, the shaft 8 for the fin 18 aligns withthe motor shaft 200, thus all of the foregoing align such that theirrotation axes are co-linear and aligned along the same axis. In theembodiment shown, the shaft 8 rotates at the same rate as the outerelement 114 and the motor shaft 200 rotates at the same rate as theinner element 104.

Referring to FIG. 16, a side partial cross section view of FIG. 10 isshown such that upper 160 and lower 162 bearings can be seen. Thesebearings are spaced apart at a distance X. The bearings support theforces generated by the fin which often includes significant bendingmoments due to the lift forces generated by the fin 18 during operationthereof. The internal height H of the stabilizer is also shown betweenwhere the shaft 8 and housing 12 meet and the maximum position of thestabilizer unit. It is understood that the bottom point where H ismeasured from is typically flush with the outer surface of the vesselhull, thus the height H represents the amount the stabilizer extendsinto the inner areas of the vessel hull. Typically space is a premium inthe areas where these stabilizers are positioned, thus a lower profilesystem is desirable. As can be seen, the drive element 4 and its motoraccomplish the mechanical advantage gearing required to move the fin 18through the water and do so in a relatively thin or small dimension.Typically, as the size of fins 18 increase, the shaft diameter D wherethe shaft interfaces the bearing housing 80 will need to increase aswill the size of the motor and drive element. The bearing spacing X mayalso need to be adjusted to account for larger or smaller moments andspace constraints available. In certain preferred embodiments the ratioof bearing spacing X to height H is 1.05-6:H (i.e. that the height H is1.05-6 times the bearing spacing X), or more particularly 1.1-5.5:H oreven more particularly 1.2-4:H, in certain embodiments 2.5-4:H others2.0-2.5:H and still others 1.2-2.0:H. As also mentioned, therelationship between the shaft diameter and height provides spaceconstraint advantages. Exemplary ranges of shaft diameter D to height Hare 2-20:H (i.e the height is 2-20 times the shaft diameter), moreparticularly 2.75-15:H or even more particularly 3.5-14:H. Certainpreferred embodiments are 4-5:H, 5-6.5:H and 6.5-12:H. It is understoodthat all modifications and adjustments within these foregoing ratioranges are contemplated. The height H represents the inboard clearancerequirements for installation of the stabilizer, i.e. if the height is12 inches, the inboard hull space must allow for at least 12 inches inspace to accommodate the stabilizer system. It is understood that thecontroller and sensors and wiring may be considered separate from theheight in instances where these elements are located in other parts ofthe vessel or in the case of wiring when it is connected such that itextends away from the stabilizer but is flexible enough to allow forconnection without interference.

It is further understood that any of the foregoing stabilizers may allowfor 360 degree rotation of the fin which is particularly useful incertain vessels such as a ferry which operates when underway in a“reverse” direction, meaning, the ferry comes into one dock bow first,off loads and then loads up and then the bow becomes the stern of theboat because the boat moves to its next destination in a manner wherethe bow is behind it, allowing offloading of cars straight off what wasthe stern at the previous dock. In this manner, the stabilizer wouldhave two neutral positions about 180 degrees apart, depending on whichside of the boat is the “front” in any given operation. Thus, thecontroller may send signals to the stabilizer to change its neutralposition by rotating the stabilizer 180 degrees such that when underway,the leading edge of the fin (right side thereof in FIG. 1) is alwaysfacing forward.

Although the invention has been described with reference to a particulararrangement of parts, features and the like, these are not intended toexhaust all possible arrangements or features, and indeed many othermodifications and variations will be ascertainable to those of skill inthe art.

What is claimed is:
 1. A vessel hull stabilizer comprising: a housinghaving a shaft mounted thereto, the shaft configured to connect to a finsuch that the fin is located on an outside of the vessel hull and thehousing is located on an inside of the vessel hull; a drive systemmounted to said housing and including a motor and a drive element, themotor connected to a central rotating element of the drive element andan outer rotating element of the drive element connected to the shaft;wherein the drive element includes a plurality of teeth positionedbetween the outer rotating element and the central rotating element suchthat when the motor rotates the central rotating element, the pluralityof teeth oscillate in a direction perpendicular to an axis about whichthe central rotating element rotates to thereby cause rotation of theouter element.
 2. The stabilizer of claim 1 wherein the motor includes ashaft which rotates about a motor axis which aligns with the axis aboutwhich the central rotating element rotates.
 3. The stabilizer of claim 2wherein the shaft configured to connect to the fin has a shaft axiswhich aligns with the motor axis and the axis about which the centralrotating element rotates.
 4. The stabilizer of claim 1 wherein the shaftrotates at the same rate as the outer element and the motor rotates atthe same rate as the central rotating element.
 5. The stabilizer ofclaim 1 wherein the shaft has a diameter measured at a first locationwhere the shaft meets the housing and the stabilizer has a heightmeasured from the first location to a maximum inboard location thereof,the shaft extending outboard from the housing from the first location;and the height is 2-20 times the diameter.
 6. The stabilizer of claim 5wherein the height is 3-15 times the diameter.
 7. The stabilizer ofclaim 5 wherein the height is 3.5-10 times the diameter.
 8. Thestabilizer of claim 5 wherein the height is 4-7 times the diameter. 9.The stabilizer of claim 1 further comprising upper and lower bearingslocated in the housing such that the shaft is supported by the upper andlower bearings, the lower bearing positioned closer to a first locationwhere the shaft meets the housing than the upper bearing, a bearingspacing measured between the upper and lower bearings and the stabilizerhas a height measured from the first location to a maximum inboardlocation thereof, the shaft extending outboard from the housing from thefirst location; and the height is 1.05-8 times the bearing spacing. 10.The stabilizer of claim 9 wherein the height is 1.1-6 times the bearingspacing.
 11. The stabilizer of claim 9 wherein the height is 1.2-5 timesthe bearing spacing.
 12. The stabilizer of claim 9 wherein the height is1.05-3 times the bearing spacing.
 13. The stabilizer of claim 1 whereinthe drive system is configured to be mounted to said housing such thatthe drive system is configured to be positioned so that the angle of themotor is adjustable to at least two different positions at least 90degrees apart.
 14. The stabilizer of claim 1 wherein the outer rotatingelement of the drive element is connected directly to the shaft suchthat the fin and the outer rotating element rotate at the same angularvelocity.
 15. The stabilizer of claim 1 further comprising: a pluralityof plates which connect to said housing, at least a first one of saidplurality of plates is a first plate and includes a central hole and aplurality of radial holes; the drive element configured to connect tothe first one of said plurality of plates at the plurality of radialholes such that an element which is caused to rotate by the motor passesthrough the central hole.
 16. The stabilizer of claim 1 furthercomprising: at least one sensor; at least one controller incommunication with the motor and the at least one sensor, the at leastone controller sends signals to the motor to change a position of thefin based on readings from the at least one sensor.
 17. A vessel hullstabilizer comprising: a housing having a shaft mounted thereto, theshaft configured to connect to a fin such that the fin is located on anoutside of the vessel hull and the housing is located on an inside ofthe vessel hull; a drive system mounted to said housing and including amotor and a drive element, the motor connected to a central rotatingelement of the drive element and an outer rotating element of the driveelement connected directly to the shaft such that the fin and the outerrotating element rotate at the same angular velocity; wherein the driveelement includes a plurality of teeth positioned between the outerrotating element and the central rotating element such that when themotor rotates the central rotating element, the plurality of teethoscillate in a direction perpendicular to an axis about which thecentral rotating element rotates to thereby cause rotation of the outerelement.
 18. The stabilizer of claim 17 wherein the motor includes ashaft which connects to the central rotating element, the rotatingelement of the motor rotates about the axis.
 19. The stabilizer of claim17 wherein the motor includes a rotating element which connects to thecentral rotating element, the rotating element of the motor rotatesabout a second axis normal to the axis.
 20. The stabilizer of claim 17further comprising: at least one sensor; at least one controller incommunication with the motor and the at least one sensor, the at leastone controller sends signals to the motor to change a position of thefin based on readings from the at least one sensor.
 21. A vessel hullstabilizer comprising: a housing having a shaft mounted thereto, theshaft configured to connect to a fin such that the fin is located on anoutside of the vessel hull and the housing is located on an inside ofthe vessel hull; a drive system mounted to said housing and including amotor and a drive element, the motor connected to a central rotatingelement of the drive element and an outer rotating element of the driveelement connected to the shaft; wherein the drive element includes aplurality of teeth positioned between the outer rotating element and thecentral rotating element such that when the motor rotates the centralrotating element, the plurality of teeth oscillate in a directionperpendicular to an axis about which the central rotating elementrotates to thereby cause rotation of the outer element; wherein theshaft has a diameter measured at a first location where the shaft meetsthe housing and the system has a height measured from the first locationto a maximum inboard location thereof, the shaft extending outboard fromthe housing from the first location; and the height is 2-20 times thediameter.
 22. The stabilizer of claim 21 wherein the height is 3-15times the diameter.
 23. The stabilizer of claim 21 wherein the height is3.5-10 times the diameter.
 24. The stabilizer of claim 21 wherein theheight is 4-7 times the diameter.
 25. The stabilizer of claim 21 furthercomprising upper and lower bearings located in the housing such that theshaft is supported by the upper and lower bearings, the lower bearingpositioned closer to a first location where the shaft meets the housingthan the upper bearing, a bearing spacing measured between the upper andlower bearings and the stabilizer has a height measured from the firstlocation to a maximum inboard location thereof, the shaft extendingoutboard from the housing from the first location; and the height is1.05-8 times the bearing spacing.
 26. The stabilizer of claim 25 whereinthe height is 1.1-6 times the bearing spacing.
 27. The stabilizer ofclaim 25 wherein the height is 1.2-5 times the bearing spacing.
 28. Thestabilizer of claim 25 wherein the height is 1.05-3 times the bearingspacing.
 29. The stabilizer of claim 21 further comprising: at least onesensor; at least one controller in communication with the motors and theat least one sensor, the at least one controller sends signals to themotors to change a position of the fin based on readings from the atleast one sensor.
 30. The stabilizer of claim 21 wherein the shaft isconfigured to rotate 360 degrees.